Wow. It's obvious that your budget is very much in line with an awesome setup.
If you can afford it, AND can source the parts, this is what I would put in it.S14 Engine
I don't know if it's within your rules or not, but as you can see, you have a few options, and either way you go, it will be a freakin' screamer!
I'm interested to know which way you go, keep me informed!